This study focuses on the effects of metallic ions, found as environmental pollutants on the immune response. Previous work from this laboratory showed that CBA/H mice treated chronically with low doses of cadmium in their drinking water developed a specific defect in the ability of their reticuloendothelial system to clear soluble immune aggregates and presumably soluble immune complexes, from their circulation. The liver is quantitatively the most important organ for normal clearance of aggregated IgG and the defect manifested by decreased liver uptake of aggregated IgG. It is proposed here to characterize the specificity and nature of this defect. This study is an important step in understanding how metallic ion pollutants affect immune processes. Implications of the study relate to eventually developing methods to monitor and identify people at high risk for immunological abnormalities due to exposure to metallic in pollutants. Awareness of immunological variables affected by environmental pollutants is important in assessment of health status of patients by health care professionals.